Social role theory originated as an effort to understand the causes of sex differences and similarities in social behavior. In the 1980s when the theory emerged, many research psychologists had begun to use meta-analytic methods to aggregate research findings bearing on the issue of whether female and male behavior differs (Eagly, 1987). These researchers had to come to terms with the persisting presence of differences in these data. Although these differences were typically not large (Eagly, 1995, 1997a; Hyde, 1996), they were often large enough to be consequential, particularly in view of the substantial cumulative impact that small differences can have if repeatedly enacted over a period of time (Abelson, 1985; Martell, Lane, & Emrich, 1995). The more accurate description of sex differences and similarities produced by quantitative reviewing, compared with earlier narrative reviewing (e.g., Maccoby & Jacklin, 1974), allowed more systematic examination of important issues such as the variation of differences and similarities across situations. More valid descriptions brought a flowering of theory, as some researchers were inspired to renew their efforts to develop theories that explain the intriguing patterns of difference and similarity present in psychological findings (e.g., Ashmore & Del Boca, 1986; Beall & Sternberg, 1993; Deaux & Major, 1987).